Compact structure photorefractive crystal hololens
A compact structure, holographic lens technology, applied in the direction of lenses, optics, optical components, etc., can solve the problems of small grating stripe spacing, small average modulation depth, low diffraction efficiency, etc., achieve strong grating, suppress scattering and fan noise, and high The effect of storage capacity
Inactive Publication Date: 2006-06-14
SHANGHAI INST OF OPTICS & FINE MECHANICS CHINESE ACAD OF SCI
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However, since the orthogonal light beam is incident on the grating formed in the photorefractive slab, the diffusion process of photoexcited free carriers is dominant, and the space charge field formed by carrier drift is limited by a saturated electric field, which makes The fringe spacing of the formed grating is too small, and the grating is weak; in addition, the normal polarized light can only be used to record the holographic grating when two light beams are perpendicularly incident, which makes the photorefraction under the condition of two light beams perpendicularly incident interference The electro-optic coefficient of the crystal is small, and the average modulation depth is small, so the diffraction efficiency of the photorefractive flat plate lens system with orthogonal incidence is not high, which limits its practical application
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[0028] see first figure 1, the structure of the compact photorefractive optical volume holographic lens system of the present invention includes two parts, the photorefractive volume holographic lens structure and the volume holographic grating lens thereon. its shape is like figure 1 The heptahedron shown can be regarded as a combination of a cuboid plate and a triangular prism made of the same crystal material. The size of the cuboid plate is a×b×c, where a>b>>c, and the thickness is c much longer than the wavelength of the incident light wave. The triangular prism is a rectangle whose base area is a×b, and the height of the triangular prism is d, which should satisfy α27°, and 2β+α=90°. When the parallel light beam 01 enters the crystal perpendicular to the incident surface 1 and propagates to the total reflection surface 3, total reflection can occur. The selection of the α angle and β angle has a certain relationship with the volume of the entire crystal structure and t...
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A photorefractive holographic lens with a compact structure, which is composed of a photorefractive crystal and a volume holographic grating on it. The photorefractive crystal is a double-doped lithium niobate crystal, and its geometric shape is composed of a A rectangular parallelepiped flat plate and a triangular prism constitute an integral heptahedron, the size of the rectangular parallelepiped flat plate is a×b×c, wherein a>b>>c, and the thickness c is much greater than the wavelength of the incident light wave, the bottom surface of the triangular prism and the The top surfaces of the parallel rectangular flat plates overlap, the size of which is a×b, the height of the triangular prism is d, the two acute angles of the triangular prism satisfy α<36°, β>27°, and 2β+α=90°, The photorefractive crystal has a volume holographic grating. The invention adopts a finite volume photorefractive holographic scheme to realize the conversion and focusing of the light beam direction in a small volume of crystal, or the transversal and collimation of the input light spot. It has small size, light weight, simple and reliable structure, high diffraction efficiency and strong anti-interference ability.
Description
technical field [0001] The invention relates to a photorefractive holographic lens, which is a photorefractive holographic lens with a compact structure using the finite volume photorefractive holographic principle, and is mainly used for space laser communication, laser radar, laser countermeasures, optical fiber communication, and miniaturization. Information optics fields such as three-dimensional optical integrated systems and miniaturized satellites. Background technique [0002] The optical lens system is a key device in the application of laser in space. The optical lens system is mainly used for laser collimation, laser emission, and laser reception. Due to the focusing effect of the traditional lens system, a certain diffraction propagation distance must be realized, which makes it occupy a large space size in the overall application system of the laser. In addition, the specific gravity of the optical glass of the lens is very high, and the weight of the support m...
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IPC IPC(8): G02B3/00
Inventor 胡志娟刘立人刘德安阎爱民王欣
Owner SHANGHAI INST OF OPTICS & FINE MECHANICS CHINESE ACAD OF SCI